Brush strip construction



June 16, 1964 R. B. ENGLISH BRUSH STRIP CONSTRUCTION Filed April 15,1962 rap/V575.

ma mu i B A H M United States Patent BRUSH STRIP CDNSTRUCTION Richardll. English, Pasadena, Calif, assignor to Industrial Brush (Iornpany,Arcadia, Calif, a corporation of California 7 Filed Apr. 13, 1962, Ser.No. 187,388

7 @laims. (Cl. 15-182,)

T his invention relates to a brush strip construction and moreparticularly to a helical or curved brush strip means especially adaptedto immovably retain brush filament material and to restrain a brushfilament retainer element against longitudinal displacement or movementwith re spect to a brush strip member during a sweeping operation.

In certain constructions of cylindrical brush means used for variousindustrial purposes, such as street sweeping, and in which thecylindrical brush means is rotated rapid ly about an axis of rotation,channel-like brush strip members carrying brush bristles or filaments,may be disposed in circular or in helical relation about said axis andare usually held by a single wire core element Within the member. Insuch a cylindrical brush means, sweeping contact of brush filaments witha surfacebeing cleaned produces bending or flexing of the brushfilaments in a direction generally parallel to the plane of the brushstrip member, or transverse to the axis of rotation. Such flexingproduces lever-like forces or stresses acting on the core retainerelement for the brush'filaments in the brush strip member, and suchforces tend to act in a ratchet-like manner to incrementally displacethe core element longitudinally of the brush strip member. Inotherwords, as a brush filament flexes, a portion of the filamentpassing beneath the wire element tends to impart a lifting forcecomponent to the core element. Since the lifting component may not be ina direct radial direction, a

small longitudinal force component is imparted'to the core element. Asthese longitudinal force components of the several filamentsprogressively act in the same direction along the length of the coreelement 'as successive filaments contact a surface during rotation ofthe cylindrical brush means, and progressive relief of suchlongitudinalforce components occurs when a brush filament is out ofcontact with the surface being cleaned, it will be apparent that eachbrush filament may act as a lever upon the core element and theplurality of filaments so acting produces a ratchet-like effect on thecore element. Thus, when the core element is a single wire of uniformcross-section, and each brush filament is in frictional contact withsuch single wire,such ratchet action produced by the sweeping operationultimately longitudinally displaces the core element so that one end ofthe core element begins to project from an end of the brush memher andbristles or brush filaments at the opposite end portion of a brush meansare loosened and will be released.

Various prior proposed devices have been employed for preventingrelative longitudinal movementof a core element in a brush strip memberprior to forming in a circular or helical arrangement. Some priorproposed devices are described in Patents 2,977,622 and 2,943,051.

In each of these patents, locking devices for the core are provided inthe form of a plurality of spaced locking clips or sleeves secured tothe core element either by friction or in some instances by soldering orbrazing. Such prior proposed devices have not'satisfactorily preventedlongitudinal displacement of'the core element after the helical brushmeans is formed and during operation of the brush means because duringformation of a helical brush strip means, the locking clips are somewhatloosened from the single core element because of stretching ofthe coreelement during formation of: the helix.

3,137,021 Patented June 16, 1964 ice The present invention contemplatesa novel brush strip constructionin which longitudinal displacement of aretainer element for the brush filaments is positively prevented andwherein additional manufacturing operations of adding locking clips andsecuring the same to the core element are eliminated. The presentinvention contemplates a brush strip construction wherein a retainerelement comprises a two strand twisted wire to provide alternatedisposition of the major dimension of the wire throughout the length ofthe wire and the brush strip construction. Thus, the twist of the twostrand wire element first disposes the major dimension of the two strandwire in vertical relation to the brush strip member and then inlongitudinal spaced relation disposes the .major dimension transverse tothe brush strip member. It has been found that such a two strand twistedwire retainer element is positively locked against longitudinaldisplacement in a brush strip member during operation and that such twostrand wire retainer element does not mate riall-y afiect or limit thequantity or the amount of brush filament material which may be desiredto be contained within a selected length of brush strip member.

A primary object of this invention therefore is to disclose and providea novel brush strip construction which solves the above mentionedproblems of prior brush strip 7 means in a novel, simple manner.

An object of the invention is to disclose and provide a novel brushstrip construction employing a retainer element having in cross-sectiona major dimension and a minor dimension, the major dimension beingprogressively (or intermittently) turned about the axis of the retainerelement so as to continuously progressively (or intermittently) changethe disposition of'the metal of the retainer element with. respect tothe brush strip. member.

Another object of the invention is. tov disclose and pro vide incombination with a channel-shaped'brush strip member and brush filamentmaterial carried by said brush strip. member, a two strand twisted'wireretainer element which cooperates with said strip. member and filamentin a manner such that longitudinal displacement of the retainer elementis prohibited during a sweeping operation.

a filament retainer element therein, and which provides positive meansfor prohibiting longitudinal displacement of a retainer element.

Various other objects and advantages of the present invention will bereadilyapparent to those skilled in. the art from the followingdescription of the drawings in which an exemplary embodiment of theinvention is shown.

In the drawings: 7

FIG. 1 is. a fragmentary sectional view of a cylindrical brush meansshowing a helical arrangement of a brush strip construction embodyingthis invention, the section being taken longitudinally of the brushmeans.

FIG. 2 isa. fragmentary enlarged side view, partially in section, of thebrush strip shown in FIG. 1;.

FIG. 3 is an enlarged sectional view taken in the plane indicated byline IH-YIII of FIG. 2.

FIG. 4 is an enlarged sectional view taken in the plane indicated byline lYI V of FIG. 2

FIG. 5 is a fragmentary side view of a retainer element embodying amodification of the invention.

FIG 6 is a sectional view taken. in the plane indicated by line VIVI ofFIG. 5. y,

In the drawings the illustration of bristle filaments is hemtaic n exe py y- In the drawings, an exemplary helical-brush means 10; maycomprise abrush; strip construction or member 3 11 embodying this invention. Thebrush means 10 provides a brush construction of cylindrical form havingan axis 12 of rotation. Such a helical brush means may be readily formedby the apparatus and method shown in application Serial No. 119,869,said application Serial No. 119,869 and the present application beingowned by the same assignee. It will be understood that while a helicalbrush means is disclosed herein by way of example, that the presentinvention will be also applicable to a cylindrical brush means formed ofa plurality of circular brush strip members because of the constantworking of the filaments on the retainer element, and that the inventionhas advantages and utility in brush strip members which are not curvedas the present example.

The brush strip member 11 may comprise a channelshaped metal brush stripmember having spaced side walls 14 joined by a bottom wall 15, said sidewalls 14 defining a top longitudinally extending opening 16 from whichmay project brush filament material 17 carried by member 11. The generalchannel-shaped Configuration of the brush strip member 11 may be variedin form and, in this example, side walls 14 may be provided with aplurality of longitudinally spaced inwardly directed indentations 18 atouter longitudinal edge portions of each side wall and in spacedrelation'to the retainer element 19, such indentations being describedin copending application Serial No. 119,869. The brush filament material17 may comprise any desired brush material including synthetic fibers,natural fibers or metal bristles. The present invention is particularlyuseful when synthetic fibers are employed because of the relativelyslippery, smooth external surfaces of such fibers which tend to reducefriction between the fibers and walls 14 and 15 of the strip member. Itwill be understood that the amount or quantity of brush filamentmaterial 17 to *be carried by brush strip member 11 with a unit oflength of member 11, may be preselected so as to provide a desired brushfilament density.

The retainer element 19 comprises a two strand twisted wire element of aconstruction similar to that produced for various industrial purposessuch as fencing and the like. The size or gauge of each strand of wiremay be selected in relation to the thickness of the brush filamentmaterial and the amount of space available between walls 14 and 15.Thus, depending upon the quantity and density of filament materialrequired and the dimensions of the brush strip member, the retainerelement-19 may be selected as to wire gauge, for example, from gauge 9to 18.

The two strand twisted wire retainer element 19 may be twisted to anyselected pitch; a suitable twisted strand may have a pitch of one turnin l or 2". The closer or smaller the pitch, the more resistance therewill be to longitudinal displacement of the retainer element duringsweeping with the brush means.

The two strand Wire retainer element has, in crosssection, a majordimension as indicated at m' and a minor dimension as indicated at n. Inthe present example of a two strand wire, it will be apparent that themajor dimension is approximately twice that of the minor dimension. Itwill be understood, of course, that in place of a two strand twistedwire, a metal bar or strip (see FIG. having an ovoidal cross-sectionwith a major and minor dimension may also be employed and that such abar may be twisted about its axis throughout its length to provideturning or twisting of the major dimension about such axis in order todispose the metal of the retainer element in progressively varyingpositions or attitudes with respect to the brush strip member. It willbe apparent that the twisted two strand wire disposes its majordimension in alternate relation at 90 intervals along the length of theretainer element 19. As best seen in FIG. 13, it will be apparent thatwhen the major dimension lies parallel to or along a longitudinal planebisecting the .brush strip member and between the sidewalls 14 that Vfolded portions 22 of the brush filament material forming bights arecompressed or deformed at the bottom wall of the brush strip member asat 23. When the major dimension is disposed transversely of thislongitudinal bisecting plane, or transverse to the side walls 14, itwill be apparent that, adjacent side walls 14, portions 24 of the brushstrip filaments aredeformed to a greater extent than their connectingportions 23. The brush filament material is thus, firmly locked withinthe brush strip member and the retainer element is immovably lockedrelative to the member 11.

It is understood that in fabrication of brush strip member 11 a selectedamount of brush filament material is uniformly distributed along anunfolded unit of length of the brush strip member, the twisted twostrand wire element laid thereover, and when the brush strip member isinitially folded and crimped into channel shape the side walls arebrought into converging grasping relation with respect to the brushfilament material; the twist or changing disposition of the metal in thecross-section of the wire retainer element will positively retain andlock the brush filament material and element in the brush strip member.

In a straight section of the brush strip member, the twisted retainerelement may not be subject to longitudinal force components which maytend to act as a ratchet to displace the retainer element since theflexing of the brush filaments is normally in a direction transverse tothe axis of the core element. However, when the brush strip element isdisposed so that the flexing of the brush filaments are in a directionparallel to the axis of a core element,

v then the ratchet-like forces acting on a core element become effectiveto produce force components tending to longitudinally displace theretainer element. The two strand twisted retainer element 19 effectivelyserves to resist such longitudinal displacement because of the variationin interlocking compressive forces made when the side walls 14 areconverged and crimped about the brush filament material and the retainerelement. The alternate disposition of the major dimension of element 19provides alternating or progressively changing stop means on element 19to prohibit displacement of the element. Such blocking againstlongitudinal displacement of the retainer element 19 is further enhancedby curving the brush strip member into circular form, or, into thecontinuous helical strip often used in street sweeping and industrialbrush means. When the brush strip member is curved about a mandrel andat the same time the two strand retainer element 19 is curved about themandrel in its assembled relation with the brush strip member and thebrush filaments, the alternate disposition in a curvilinear path of themajor dimension of the retainer element provides an additionalrestraining effect upon the core element and the wire retainer elementis positively prevented from longitudinal displacement.

It will thus be apparent to those skilled in brush making that theretainer element, formed with a major and minor dimension and with saiddimensions alternately arranged throughout the length of the element,positively cooperates with the brush filament material and the brushmember to prohibit relative movements of the retainer element, brushfilamentsyand brush member during operating conditions whether severe ornormal. Longitudinal displacement of the retainer element afterformation of the brush means is effectively and simply prevented.

While the retainer elements of FIGS. 2 and 5 exemplarily illustrate arelatively uniform pitch or twist, it is contemplated that the twist insuch bar stock may occur .in ashort section of the element, that is, arapid twist is made. Between such short twisted sections, relativelylong straight non-twisting sections may be provided in alternatevertical and horizontal relation. In addition, a wire or bar stock ofsuitable cross-section, such as circular or square, may be deformed asby horizontal and vertical pressure rolls to provide alternatedispositions of major and minor dimensions of deformed portions of thebar stock. i

It will be understood that the twist or pitch of the retainer elementmay occur in random fashion with respect to the'indentations in thewalls 14, in other words, the spacing of the indentations is notnecessarily related to the twist of the retainer element and anindentation may occur opposite horizontal or vertical dispositions ofthe retainer element.

All modifications and changes of the retainer element and the brushconstruction disclosed herein and coming within the spirit of theinvention and scope of the claims appended hereto are embraced thereby.

I claim:

1. A brush strip construction comprising: a curved, channel-shapedmember having spaced side walls and a bottom Wall; a retainer elementconsisting essentially of only two twisted strands Within saidchannel-shaped member having a selected pitch to alternately presentdistinct major and minor diameters and curved therewith; and brushfilaments folded in said member between said walls and said retainerelement; the twist of the two strand retainer element being cooperablewith said brush filaments and said channel-shaped member to'frictionallyretain said element against longitudinal movement relative to saidchannel-shaped member.

2. In a brush strip means, the provision of: a channelshaped memberhaving side walls in spaced relation to a longitudinal plane bisectingsaid member and passing between said side walls; brush filament materialcarried by said channel-shaped member; and a retainer element separatefrom said brush filament material and carried in said member forfrictionally retaining the filament material in the member, saidretainer element having in to said longitudinal plane wherebylongitudinal movement of the retainer element relative to said filamentmaterial and member is inhibited.

3. In combination with a brush strip member and brush filament materialcarried by said member, the provision of: a retainer element separatefrom said filament material and member and having major and minordimensions in cross-section, said major dimension being disposed inalternate 90 relation at spaced intervals to restrain relativelongitudinal movement of the element with respect to the filamentmaterial and the member.

4. In combination with a brush strip member and brush material carriedby said member, the provision of: 3.

retainer element separate from the member and brush 'material having incross-section a major dimension which is at least substantially twicethat of a minor dimension ii thereof; said major dimension beingprogressively turned about the longitudinal axis of the element forrestraining longitudinal displacement of said retainer element withrespect to said brush strip member.

5. In combination with a brush strip member and brush filament materialcarried by said member; a twisted wire retainer element consistingessentially of only two strands within and overlying said member, saidretainer element being within a fold of said brush material.

6. A brush strip means comprising in combination: a brush strip memberhaving side walls and a bottom wall defining a longitudinal channel;brush filaments extending outwardly from said channel and having afolded portion in said channel; a retaining element lying in said foldedportion and cooperable with said side and bottom walls to hold saidbrush filaments in said chamber, said retaining element having meansrestraining longitudinal movement of the element relative to the wallsand filament, said restraining means including an elongatedcrosssectional disposition of metal presenting major and minordimensions throughout the length of the retainer element, and saidelement being turned about its longitudinal axis to alternately positionsaid major and minor dimensions whereby said retainer element isalternately locked with respect to said brush filamentsand side wallsand said brush filaments and bottom wall.

7. A brush strip means comprising: a channel-shaped member havingsubstantially opposite facing side walls joined together by a bottomwall; a plurality of brush filaments; each brush filament having afolded portion which forms a bight snugly disposed within saidchannelshaped member; a retainer element separate from the brushfilaments and disposed within the bights; said re tainer elementconsisting essentially of only two twisted wires which are insubstantially continuous engagement with one another so as to present asingle major dimension at least substantially twice the size of a singleminor dimension as seen in consecutive transverse cross-sections of theretainer element, whereby at transverse cross-sections said bights aresignificantly flattened along the major dimensions to prevent movementof the retainer element relative to said brush filaments.

References Cited in the file of this patent Germany Nov. 3, 1 930

5. IN COMBINATION WITH A BRUSH STRIP MEMBER AND BRUSH FILAMENT MATERIALCARRIED BY SAID MEMBER; A TWISTED WIRE RETAINER ELEMENT CONSISTINGESSENTTIALLY OF ONLY TWO STRANDS WITHIN AND OVERLYING SAID MEMBER, SAIDRETAINER ELEMENT BEING WITHIN A FOLD OF SAID BRUSH MATERIAL.